Testing in Austria is complete, and a total of six unique sites were evaluated for tire-pavement noise using OBSI and texture via RoboTex. Each of the sites was constructed using exposed aggregate concrete (some 8 mm maximum aggregate size, others 11 mm). The sites span a period of 15 years of construction.

OBSI data has been collected using the 16-in SRTT tire at 60 mph (97 km/hr), and a preliminary analysis has revealed that total OBSI levels are on the order of 104 to 106 dBA (ref 1 pW/sq.m). These levels are similar to those previously measured on exposed aggregate sections in both Michigan and in Montreal. To further reference these measurements, note that the quietest dense concrete pavement in the USA is on the order of 99 dBA, while the surfaces with the highest levels can be over 110 dBA.

Here is a little info about each of the Austrian sites:

Site AT01 is located on the A2 near Vösendorf (south of Vienna). It was constructed in 2005/2006. Due to traffic levels, it was only measured using OBSI.

Site AT02 is located on the A1 near Erlauf, approximately 60 miles West of Vienna. It was constructed in 2000 with 11 mm aggregate.

Site AT03 and AT04 are in opposite directions of the A1 at the same location: near Tödling, about 100 miles West of Vienna. Both were constructed with 8 mm aggregate, but Site AT03 was constructed in 2000 and AT04 in 1998.

SIte AT05 is on the A1 near Steindorf (Seewalchen am Attersee) – approximately 35 miles East of Salzburg. It was constructed using 11 mm maximum aggregate size in 2001.

Site AT06 is on the A1 near Thalgau, 15 miles East of Salzburg. It is the oldest of the sites tested; constructed in 1992 using 8 mm aggregate.

The following figures reveal both the total OBSI levels and the corresponding spectra. Each site was approximately 1 to 1.5 km in length. To expand each figure, click on it.

Much appreciation is given to VÖZ, ASFINAG, and the various Autobahnmeisterei for their assistance in the measurements.